When I open blender, my textures and materials turn bright pink?
This means that Blender can't find your textures. So you either moved or deleted these textures. Simply relocate your textures for your material and it will look like normal. You can pack all of the external data (images, sound files, video files and appended data) into your blend file but this will heavily increase the size of it, to do this: File> External Data> Pack all.